Anterior Interosseous-to-Ulnar Motor Nerve Transfers: A Single Center's Experience in Restoring Intrinsic Hand Function.

Background: Transfer of the anterior interosseous nerve (AIN) into the ulnar motor branch improves intrinsic hand function in patients with high ulnar nerve injuries. We report our outcomes of this nerve transfer and hypothesize that any improvement in intrinsic hand function is beneficial to patients. Methods: A retrospective review of all AIN-to-ulnar motor nerve transfers, including both supercharged end-to-side (SETS) and end-to-end (ETE) transfers, from 2011 to 2018 performed by 2 surgeons was conducted. All adult patients who underwent this nerve transfer for any reason with greater than 6 months' follow-up and completed charts were included. Primary outcome measures were motor function using the British Medical Research Council (BMRC) grading system and subjective satisfaction with surgery using a visual analog scale. Secondary outcome measures included complications and donor site deficits. Results: Of the 57 patients who underwent nerve transfer, 32 patients met the inclusion criteria. The average follow-up and average time to surgery were 12 and 15.6 months, respectively. The overall average BMRC score was 2.9/5, with a trend toward better recovery in patients who received earlier surgery (<12 months = BMRC 3.7, ≥12 months = BMRC 2.2; P < .01). Patients with an SETS transfer had better results that those with an ETE transfer (SETS = 3.2, ETE = 2.6). There were no donor deficits after operation. One patient developed complex regional pain syndrome. Conclusions: Patients with earlier surgery and an in-continuity nerve (receiving an SETS transfer) showed improved recovery with a higher BMRC grade compared with those who underwent later surgery. Any improvements in intrinsic hand function would be beneficial to patients.